Ok, I went to Home Depot yesterday, and was speaking to a guy in the lumber department. He made it sound that if I used "untreated" lumber, insects/ants/whatever would burrow into the wood and have a field day. He said I MUST use treated lumber for building outside.

So to confirm, most of you use untreated lumber AND untreated plywood to build your coops and have no problem? After you build, do you use any kind of wood preservative? Thanks so much, by the way I'm new here (have been lurking for awhile), and have gotten so much great info. My 4 chicks will arrive from Meyer on Tuesday.

IMHO, and I am certainly no expert, you really only need treated wood for parts that are going to be in the ground or in contact with the ground. Anything above ground will last for a very long time made out of regular wood if it is painted or protected from the weather (inside framing for example). Even if not painted or protected, it will last pretty long. An alternative to pressure treated wood is Trex or any other brand of recycled lumber. However, it is either hard to find or very expensive to get certain dimensions of lumber. (Its easy to find 3/4" x 5 1/8" deck planks) I hate pressure treated but I think I am going to use 4x4 posts to cement in the ground to hold my coop up and then everything above that will be regular pine. I am still pondering the run and how to keep pressure treated to an absolute minimum. Good luck! As soon as I move my wood pile and my foot is better, I will be building my coop and run too! Chicks arrive 7/23!

What bluie says. You only need rot-resistant (see below) lumber for parts that are in direct contact with the ground... posts, foundation sills, that sort of thing. Everything else can, and probably SHOULD, be made of regular ol' untreated wood. (BTW good luck finding and using pressure-treated plywood - it is hard to get, and unless you get the extremely expensive marine-grade plywood it is really cr appy stuff, with splinters and voids and warping and such.)

The main part of the coop, made of normal materials, needs to be primed and painted (or at least stained and then re-sealed every year or two), but as long as you do that properly it will last Plenty Long Enough.

Remember, HOUSES are not made of pressure-treated wood, not even the parts where wood is exposed to the weather - porches, wood siding, etcetera

For the parts of the coop and run that DO need to be rot resistant, you have three basic choices:

2) Cedar, redwood, or locust. About twice the price of pressure treated, but all-natural and generally lasts at least as well.

3) Trex or other wood-fiber-and-plastic composite product. Even more expensive than cedar usually, and made w/petrochemicals albeit recycled ones. Has different structural characteristics than wood - bendier - that sometimes need slight modifications of your construction plans.

I'd use treated for the areas that touch the ground, or are underground. Otherwise, it will rot. For the other parts, if you're worried about it, just paint it. Even if you don't, it's not like it will fall apart for awhile. I've been using a sheet of unfinished OSB as a pistol target for 2 rain and snow filled years, and it still works fine.

place some 12" x 12" x 4" cement blocks on the ground and level them all to one another. so that all are the same height. you might have to add dirt or take away dirt underneath them.
then start off with treated 2x 10's or 2x 12's then to get it off the ground a good bit, then use regular wood from there which should painted, etc..

Guys: I am wanting to add an insulating layer inside my coop. Some styrofoam and then plywood over that. Should I put something on the plywood to help with the moisture of cleaning? Since I will be scrubbing it down ? If so, what??